Flansburgh even found time to moonlight as a video director, helming clips for Ben Folds Five, Harvey Danger, Soul Coughing, Edwyn Collins and Frank Black, in addition to two videos for his own band.

While many other bands who emerged from the same mid-’80s alternative explosion burned out a few years later, TMBG persevered on their own terms with a work ethic to rival a Harvard grad student. After two decades of working together, the Johns, childhood friends from a Boston suburb, have got this making-music thing down to a science.

“We both have project studios, so we can do double duty,” Flansburgh said. “John can be in one room and I can be in another room and we can work with other people and get a lot of stuff done quickly. Sometimes that’s necessary, because we created insane deadlines for ourselves. The other thing is that we’ve just been around forever and have a backlog of stuff, and we work really efficiently [with it]. We don’t write in the studio. We’ve been kind of allergic to that ever since the beginning, when we were poor enough that we couldn’t do that. We try to get everything mapped out in our project studios, and we both are kind of uptight and not into wasting time, so we try to do everything pretty quickly, and that’s a good way to work.”

Their intense regimen has most recently produced the new theme music to “America’s Most Wanted,” scheduled to debut in May; the companion soundtrack to McSweeny’s Literary Journal’s Art & Music Issue #6; “Now That You’re One of Us” for the film “Return to Neverland”; the themes to the WB’s animated series “The Oblongs” and Comedy Central’s “The Daily Show”; music cues for ABC’s “Nightline Primetime”; music for a Diet Dr. Pepper commercial; and No!, a 17-track children’s album due June 11, as well as their latest LP, Mink Car, released last fall.

The recording of the album and the events leading up to it are captured in “Gigantic (A Tale of Two Johns),” a documentary marking the 20th anniversary of TMBG’s first show. The film premiered March 10 at the South by Southwest Film Festival and will move on to the film festival circuit before a still-unscheduled commercial release.

Director A.J. Schnack began filming “Gigantic” last March and finished just two weeks before the premiere. Shot in London and the U.S., the film chronicles the Johns’ early days of growing up in Lincoln, Massachusetts, to first writing songs together in high school, to moving to Brooklyn, New York, where they started the Dial-a-Song phone hotline while shopping around their demos to labels. For 20 years and counting (call (718) 387-6962 and see for yourself), Dial-a-Song has offered fans the chance to hear early demos and random musical musings, a promotional tool that helped develop the band’s local following even before they released their 1986 self-titled debut. A collection of some of the “outgoing musical messages,” Dial-a-Song: An Anthology, will be released in August.

TMBG’s second effort, Lincoln, was the best-selling indie album of 1989, and its successor, 1990’s gold-certified Flood, berthed the group’s nationwide breakthrough single, “Istanbul (Not Constantinople).” Three other albums followed, each possessing the distinctive TMBG trademark of accordion-bellowed melodies, whiney vocals and songs sometimes too clever for their own good.

Mink Car, however, bucks the Giants’ system of keeping everything under control and allows outside hands – including those of producers Clive Langer, Alan Winstanley, Fountains of Wayne singer/songwriter Adam Schlesinger and Pat Dillett – into the frey. The result is album that shows the duo at their most adventurous.

“We were really doing it in pieces,” Linnell said of recording Mink Car while also working on incidental music for the new season of “Malcolm.” “We were approaching the idea like, ‘How can we create a breakthrough song with you?’ It was not like our regular album experience. We really wanted to make a really strong record.”

“We always want to make strong records,” Flansburgh clarified, “but in this case we also were at the point where we were confident enough to give stuff to people and say, ‘Go completely crazy.’ Well, maybe they didn’t go completely crazy, but they did stuff that we would have never have done ourselves. They were doing stuff that was kind of un-Giants.”

Perhaps the most un-Giant-like of the bunch are the tender, pop-lite strum of “Another First Kiss,” featuring crooned-not-whined vocals, and the disco-inspired “Man, It’s So Loud in Here.” The latter lives at the polar opposite of the TMBG spectrum, with its steady throb of staccato beats. Even the biggest fan might not identify the track’s creator, until, that is, the curmudgeonly funny lyrics surface. A comment on the social dynamic within a dance club, the song depicts a one-sided conversation between a club kid who attempts to hold his interest’s interest with “Baby, check this out, I got something to say/ Man, it’s so loud in here/ When they stop the drum machine and I can think again, I’ll remember what it was.”